Refactor media out of WebContentsImpl to MediaWebContentsObserver.

content/test/web_contents_observer_sanity_checker.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/test/web_contents_observer_sanity_checker.h"
 
 #include "base/strings/stringprintf.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/common/frame_messages.h"
 #include "content/public/browser/navigation_handle.h"
@@ skipping 60 matching lines @@
   } else if (!was_live) {
 // TODO(nick): Clients can easily ignore an unrecognized object, but it
 // would be useful from a finding-bugs perspective if we could enable this
 // check.
 #if 0
     CHECK(false) << "RenderFrameDeleted called for routing pair "
                  << Format(render_frame_host)
                  << " for which RenderFrameCreated was never called";
 #endif
   }
+
+  // All players should have been paused by this point.
+  CHECK(active_media_players_.empty());

[ncarter (slow), 2015/12/05 00:43:33]

This CHECK needs to depend on |render_frame_host|, since there's nothing
stopping other existing frames from playing content.

You can repro this easily: have a page with an iframe. Have the main document
play media, and meanwhile remove the iframe from the document.

[DaleCurtis, 2015/12/05 01:18:02]

Whoops, yeah, done.

 }
 
 void WebContentsObserverSanityChecker::RenderFrameForInterstitialPageCreated(
     RenderFrameHost* render_frame_host) {
   // TODO(nick): Record this.
 }
 
 void WebContentsObserverSanityChecker::RenderFrameHostChanged(
     RenderFrameHost* old_host,
     RenderFrameHost* new_host) {
@@ skipping 154 matching lines @@
 void WebContentsObserverSanityChecker::DidOpenRequestedURL(
     WebContents* new_contents,
     RenderFrameHost* source_render_frame_host,
     const GURL& url,
     const Referrer& referrer,
     WindowOpenDisposition disposition,
     ui::PageTransition transition) {
   AssertRenderFrameExists(source_render_frame_host);
 }
 
+void WebContentsObserverSanityChecker::MediaStartedPlaying(
+    const MediaPlayerId& id) {
+  CHECK(!web_contents_destroyed_);
+  CHECK(std::find(active_media_players_.begin(), active_media_players_.end(),
+                  id) == active_media_players_.end());
+  active_media_players_.push_back(id);
+}
+
+void WebContentsObserverSanityChecker::MediaPaused(const MediaPlayerId& id) {
+  CHECK(!web_contents_destroyed_);
+  CHECK(std::find(active_media_players_.begin(), active_media_players_.end(),
+                  id) != active_media_players_.end());
+  active_media_players_.erase(std::remove(active_media_players_.begin(),
+                                          active_media_players_.end(), id),
+                              active_media_players_.end());
+}
+
 bool WebContentsObserverSanityChecker::OnMessageReceived(
     const IPC::Message& message,
     RenderFrameHost* render_frame_host) {
   // FrameHostMsg_RenderProcessGone is special internal IPC message that
   // should not be leaking outside of RenderFrameHost.
   CHECK(message.type() != FrameHostMsg_RenderProcessGone::ID);
 
 #if !defined(OS_MACOSX)
 // TODO(avi): Disabled because of http://crbug.com/445054
   AssertRenderFrameExists(render_frame_host);
 #endif
   return false;
 }
 
 void WebContentsObserverSanityChecker::WebContentsDestroyed() {
   CHECK(!web_contents_destroyed_);
   web_contents_destroyed_ = true;
   CHECK(ongoing_navigations_.empty());
+  CHECK(active_media_players_.empty());
 }
 
 WebContentsObserverSanityChecker::WebContentsObserverSanityChecker(
     WebContents* web_contents)
     : WebContentsObserver(web_contents), web_contents_destroyed_(false) {
   // Prime the pump with the initial objects.
   // TODO(nasko): Investigate why this is needed.
   RenderViewCreated(web_contents->GetRenderViewHost());
 }
 
@@ skipping 33 matching lines @@
       render_frame_host->GetSiteInstance()->GetSiteURL().spec().c_str());
 }
 
 bool WebContentsObserverSanityChecker::NavigationIsOngoing(
     NavigationHandle* navigation_handle) {
   auto it = ongoing_navigations_.find(navigation_handle);
   return it != ongoing_navigations_.end();
 }
 
 }  // namespace content